In general, a mobile phone has a function of reporting to a user the existence of an unanswered call (“missed call”) where a call signal has not been answered even when arriving. For example, the missed call is reported by displaying as “missed call” or another message near the center of a standby screen, by displaying that there was a missed call by using a graphic referred to as a “pict” in a top or bottom dedicated area of the screen, or by turning on an LED or other light emitting element.
Further, also in a case where not only arrival of a call, but also arrival of an e-mail (arrival of new mail) occurs, the arrival of the e-mail is reported to the user by a method similar to that in the case of the call.
The display of such a missed call is usually erased by a user performing a predetermined check operation. For example, in the case of a call, the display is erased by displaying a screen of the incoming call history. While in the case of an e-mail, the display is erased by receiving new mail from a server and displaying that received mail on the screen. Even if the user performs a different operation from this, the display of the missed call is not erased.
Further, in many mobile phones, together with messages of missed calls, buttons for directly shifting to screens for the incoming call history and mail reception are displayed as soft keys. If the user depresses a button corresponding to this display to shift to such a screen, the message of the missed call is erased from the standby screen.
In recent years, the modes of communication by phones have been diversifying. In addition to conventional voice calls by line switching, phones capable of performing packet communication utilizing an IP (Internet Protocol) network are being widely utilized. For example, there is known “chat mail” where mobile phones engage in conversations by trading text in real time (see Patent Document 1). Chat mail is one of the modes of communication called “group communication” where preregistered members form a group and trade text or other data in real time in the group.
Further, as one of the modes of group communication attracting attention recently, there is the one called PTT (push to talk) or PoC (push to talk over cellular). In PTT, a plurality of communication apparatuses forming a group engage in voice calls in real time by VoIP (Voice over Internet Protocol) (see Patent Document 2).
In group communication of PTT, a user desiring to say something pushes a predetermined button (PTT button) provided at the communication apparatus, whereby a speak request of the user is sent to the server apparatus. The server apparatus receives speak requests from the different communication apparatuses and gives a right of speech to one communication apparatus. The communication apparatus given the right of speech transmits audio data of the user to the server apparatus. Then, the server apparatus transmits the voice data to the other communication apparatuses all together. Due to this, a plurality of communication apparatuses forming a group engage in a voice call in real time.
Patent Document 1: Japanese Patent Publication (A) No. 2003-174520
Patent Document 2: Japanese Patent Publication (A) No. 2005-522067